Backpack



FIG. 1 is a front view of a backpack embodying my new design;

FIG. 2 is a left side view of the backpack of FIG. 1, the right side view being substantially identically identical thereto;

FIG. 3 is a rear view of the backpack of FIG. 1;

FIG. 4 is a top view of the backpack of FIG. 1; and,

FIG. 5 is a bottom view of the backpack of FIG. 1.

The broken line showing of strope in FIGS. 1-5 and the broken line showing of a zipper pull in FIGS. 1-5 are for illustrative purposes only and form no part of the claim. 

Th ornamental design for a backpack, as shown and described. 